Where and when did the notion that pregnant women should “eat for two” originate? How much weight has medicine advised pregnant women to gain over time?

Heads Up: This is a lengthy piece (even for me).

I thought the concept of “eating for two” probably originated in the 1960s or 1970s as a cushy “what-to-expect” backlash again previously stringent weight-gain recommendations. I was wrong. I couldn’t even find the phrase’s beginnings. Apparently, women and doctors have been trying to rebut the eating for two myth since the 1800s.

Check out these nuggets:

In an 1866 advice manual, E.G. Cook stated: “the idea is erroneous that it is well ‘to eat for two people.’”[1]

In an 1891 book titled Parturition without Pain: Code of Directions for Escaping from the Primal Curse (nineteenth-century authors had a gift for composing undisguised, precise titles, didn’t they?), M.L. Holbrook described the notion of “eating for two” as a “common error” and a “thorough delusion,” besides being an absurd idea.[2]

In her 1901 handbook, What a Young Wife Ought to Know, Emma F. Angell Drake urged that “the false notion that the pregnant woman ‘must eat for two,’ and so proceed to indulge her appetite to the utmost, should be corrected.”[3]

In a 1919 medical text on fetal nutrition, Morris J. Slemons explained that “popular opinion holds that during pregnancy the mother ‘should eat for two.’ This doctrine is erroneous.”[4]

“It may surprise you,” shared Carolyn C. Van Blarcom in her 1922 guidebook ,Getting Ready to be a Mother: A Little Book of Information and Advice for the Young Woman Who is Looking Forward to Motherhood, “to learn that you need not ‘eat for two,’ in quantity, as is so commonly believed necessary . . . .” [5]

In a 1935 maternity care book, Claude Edwin Heaton remarked that “there is no foundation for the old belief that the pregnant mother must eat for two.”[6]

In the Pennsylvania Medical Journal in 1949, Robert Willson explained that “the ancient belief that the pregnant patient must ‘eat for two’ has no basis in fact since the additional dietary needs during pregnancy are only slightly greater than for the non-pregnant woman.”[7]

In a 1962 piece in The Lancet, Albert Bauer lamented that “unfortunately, the old axiom that the expectant mother should ‘eat for two’ is still widely accepted by the public and even by some of our profession.”[8]

I could go on, but the point is clear: Americans have been working to expose the notion that pregnant women should “eat for two” as a misconception for hundreds of years.

So, if medicine has never endorsed the “eating for two” meal plan, what did it recommend in terms of women’s weight gain?

Medical practitioners may have been united in their historical disavowal of eating for two, but they agreed on little else about weight gain during pregnancy. From the late 1800s onward, advice to pregnant women about how, when, what, and how much to eat changed like the wind. This piece focuses (almost) exclusively on one of those components: the question of how much weight women should gain, ideally, during a normal, healthy pregnancy. The science of nutrition is one of the most complex, least understood components in human health, and thus in some ways it is no surprise that medicine’s understanding of nutrition during pregnancy has always been lacking. And yet the extent of this void in information is still remarkable.

This piece explores how the ideas about weight gain during pregnancy have changed since the late 1800s. We’ll go on a chronological tour of advice about eating and weight during pregnancy, discuss the major debates over time, review some of the historical constants, and finally, try to draw some sense from this story.

Since at least the mid/late-1800s, commentators have been concerned with pregnant women’s diets. Around the turn of the century, they generally opined that healthy eating was significant to a healthy pregnancy, but that a woman did not need to eat much more (if at all) while she was pregnant, except perhaps towards the very end of her pregnancy. “There is no diet specifically adapted to the state of pregnancy,” one textbook explained. “A diet which has previously been ample will likewise be sufficient throughout pregnancy.”[9] Within this broad framework, advice literature provided detailed directives regarding pregnant women’s food consumption. Most centered on strategies for minimizing it. In lieu of summarizing these tips, here are:

The Top Five Commandments of Eating While Pregnant, around 1900:

1. Thou Shalt Eat as Thou Normally DoesThe idea that pregnant women should continue eating as they typically ate abounded. “In normal pregnancy there is no indication for a special diet. You should eat the foods you are accustomed to and enjoy, provided a well-balanced diet is taken,” wrote one commentator.[10]As another put it, “the woman who is eating correctly anyways, will not have to vary her diet during pregnancy.”[11]

2. Thou Shalt Masticate Thoroughly Writers were very adamant that women chew their food very fully.[12]

3. Thou Shalt Not Foolishly Gratify Thy Whims and Longings (or, Thou Shalt Constantly Guard Against Overeating)[13]Women were warned not give in to culinary temptation or cravings.[14] They were not to “be persuaded to humor and feed [their appetite’s] waywardness.”[15]Instead, women learned that their appetites “should be kept under in pregnancy as carefully as at any other time, rather than otherwise.”[16]

The first commandment informed every other: at the heart of turn-of-the-century ideas about weight gain during pregnancy was the broad notion that pregnant women did not need to eat much more or differently than anyone else, especially given the prevailing sentiment that most Americans ate too much to begin with.

“The fact is more likely,” described M.L. Holbrook, “to be the seeming paradox that enough for one is too much for two.”[19]Into the early 1900s, as the origins of modern prenatal care emerged in the U.S., actual numbers began to figure in to conversations about pregnancy and nutrition. Recording weight quickly became part of the routine prenatal visit, and keeping numbers low became increasingly important. By mid-century, it was standard to measure a pregnant woman’s weight at every visit, at least partly as a strategy to limit gain.[20]One doctor reflected that in the 1950s, prenatal exams were centered on the weigh-in.[21]Already by the 1920s, doctors endeavored to limit maternal weight gain to just 15 pounds – mostly in attempt to facilitate smoother labors and deliveries, but also to “preserve the woman’s figure after birth.”[22] The lower the gain, the better.

The Mid-1900s: Watch Your Weight, Pregnant Ladies For the most part, medicine maintained, if not intensified, this strict advice throughout the mid-1900s. “The need for limiting weight gain during pregnancy is almost universally accepted. A strict diet regimen is essential in most cases,” expressed one research group in its article “Control of Weight Gain in Pregnancy.”[23] The sentiment that pregnant women did not need any extra food proliferated in this “era of stringent dietary restriction.”[24]As the 1950 edition of WilliamsObstetrics stated: “in normal pregnancy the diet should be no more or less than that to which the patient has been accustomed.”[25]

The standard guidance was that women should only gain between 15 and 18 pounds (some even thought 15 pounds should be the upper limit) – just enough to account for the “matter” of pregnancy (a fetus, the placenta, extra blood volume, etc.).[26]“The individual who begins pregnancy at her normal weight need gain no more than the amount she will eventually lose following delivery and the completion of lactation,” explained physician Robert Willson.[27]

This was urgent advice, to the extent that physicians regularly prescribed medications to assist with the goal of minimal weight gain. (They doled out diuretics and various amphetamines, including dexadrine sulfate – now used to treat ADHD symptoms and narcolepsy – to limit fluid retention and curb appetites.)[28]Whether they resorted to pharmaceuticals or not, doctors tended to be insistent about this. “I suspect a fair number of our patients are made quite miserable throughout their pregnancy,” observed one obstetrician, “by our zeal in stressing this phase of prenatal care [weight gain].”[29]

Importantly, some outlying physicians did take issue with these limitations, and advised their patients differently. Some “let” women gain 30 pounds. Others simply thought the imposed limits were unjustified. One physician at the University of Pittsburgh remarked that “the routine, rigid restriction of a pregnant woman’s diet is inappropriate and unwise, and places an unfair emotional strain on the mother-to-be. Doctors should base diet advice on the specific nutritional needs of the individual patient, not arbitrary weight scales and charts.”[30] Perhaps it was from this initial seed of dispute that things began to change in the 1970s.

From Willpower to Starvation: Changing Ideas in the 1970s and 80sUp until 1970, the overwhelming practice among U.S. obstetricians was to curb weight gain during pregnancy as much as possible. In 1970 the National Academy of Sciences National Research Council (NAS) released a set of guidelines that initiated a new trend: “liberalizing weight guidelines and viewing [dietary] restriction as a form of relative starvation.”[31] The NAS report encouraged pregnant women to “eat to appetite” and aim for the “normal” weight gain of 24 pounds. This was a major turning point, a clear break from the harsh limits set in the past.[32]

The fresh, relaxed perspective stemmed from concerns about underweight babies (and, tangentially, the nation’s atrocious infant mortality rates).[33]The NAS expressed that ungrounded recommendations limiting women’s weight gain were “in effect contributing to the large number of low-birth-weight infants and to the high perinatal and infant-mortality rates” nationwide. Instead of protecting women and babies, in other words, the NAS report implied that doctors’ widespread habit of preventing pregnant women from gaining weight was harming them.[34] Soon after, U.S. medicine started forwarding a more liberal idea of the ideal weight gain range: 20-25 pounds.[35] Some texts permitted 30 or even 35 pounds.[36]New laws mandated that diuretics labels indicate that pregnant women should not take them.[37] Williams Obstetrics began warning practitioners about the dangers – rather than the merits – of severe dietary limitations.[38]

By the 1980s things were very different: New York Times health correspondent Jane Brody described that the “widespread practice among obstetricians” was to encourage “maximum weight gain during pregnancy” – a far cry from decades prior.[39] (That was not exactly true – the broad recommendation was to gain between 20 and 30 pounds, but it understandably appeared unbridled compared to the previous limitations.[40]) Furthermore, doctors in the 1980s were much more anxious about pregnant women gaining too little weight.[41]

The 1990s: Controversy Sowed In 1990 new guidelines advised individualized recommendations based on women’s pre-pregnancy weight. Instead of a blanket weight gain range, the new advice circumscribed various ranges depending on a woman’s body mass index (BMI) when she became pregnant.[42] For women with a normal BMI, a gain of between 25 and 35 pounds was considered appropriate. Thus, a weight gain of 30 pounds was “normal,” where it would have been regarded as “excessive” or “dangerous” a few decades earlier.[43](As a further note here, the 1990 recommendations were a milestone – it was the first time that recommendations varied by pre-pregnancy weight. But doctors have been doling out different advice about weight gain to different women, depending on their weight, for some time. Since at least the 1930s, medical articles and public health publications have consistently expressed that underweight women might need to gain more during pregnancy and overweight patients might need to gain less.[44]) The even-more tolerant 1990 guidelines met a wave criticism. Many researchers thought the new recommendations were far too broad and needed more evidence.[45] One article in The Lancet encapsulated many of critics’ fears. “The evidence for a population-wide strategy of liberal weight gain during gestation is weak in industrial nations,” the authors wrote, “and . . . this potential harmful policy represents an inappropriate response to problems rooted in inadequate preconception/prenatal care and social deprivation.” They noted that expecting mothers should probably gain at least around 15 pounds, but warned that the new 25-35 pound allowance fell “in the opposite direction.” Although the directive was intended to improve infant welfare, the study explained, “a logical policy response is surely not to encourage overnourishment in all pregnancies, but rather to promote preconceptual nutritional counseling and close monitoring of third-trimester weight gains for thin women.” Essentially, these authors considered the liberalized weight gain guidelines a “misguided” attempt to solve the problem of low birth weight. “We are at a loss,” they concluded, “to understand the logic of encouraging millions of women to overeat during pregnancy . . . .”[46]

The 21st Century: Controversy Continued In the 2000s and beyond, the back-and-forth about “ideal weight gain” during pregnancy continues. Many researchers are especially concerned about implications for the obesity epidemic. More and more physicians are questioning what constitutes “excess” weight gain during pregnancy, and how it might be linked to long-term weight as well as public health.[47]Some of them see pregnancy as a unique window to combat the obesity epidemic: “putting the brakes on weight gain during pregnancy may be an opportunity . . . to break the cycle of obesity,” one reporter summarized. “Similar to smoking-cessation programs, pregnancy provides a unique opportunity for behavior modification given high motivation and enhanced access to medical supervision . . . Pregnancy is an optimal time for health care providers to offer their resources to decrease maternal obesity and comorbidities, thus affecting current and future generations.”[48] The American College of Obstetricians and Gynecologists (ACOG) issued its most recent committee opinion on weight gain in pregnancy in 2013 – it reflects the NAS guidelines, and is stratified by BMI: (If you don’t know your BMI, you can check it using this calculator from the CDC.):

ACOG’s own statement acknowledges that many critics regard these guidelines as excessive (particularly for the higher BMI categories), but encourages physicians to rely on these recommendations as a “basis for practice.”[50]

​Central Threads of Conversation Over TimeDigging deeper, a handful of issues stand out as predominant concerns for why any of this has mattered in the first place. In other words, society and medicine have considered pregnant women’s weight important (and sought to better understand it) for different reasons at different times (clearly).In identifying key points of discussion, there is a constant tension between mom and baby –does weight gain matter more for a mother’s health, or for a baby’s? The answer, of course, is both, but doctors and mothers alike have expressed variable priorities over time. Here are some of the central, consistent threads of conversation coloring the history of “eating for two.”

1. Fetal Size Research has gone back and forth on the question of whether maternal weight gain is a determining factor in fetal size since the nineteenth century. In the 1800s, doctors thought that women who gained less weight while they were pregnant gave birth to smaller babies, and they considered this desirable because they judged that birth would be easier (and safer) with smaller fetuses. (It didn’t hurt that this also aligned with prevailing ideals of feminine beauty – i.e., that women be slender mothers). Later, obstetricians who could rely on much safer birthing rooms and C-sections produced evidence indicating that smaller babies were, generally, less healthy than heavier babies. Thus, growing a smaller fetus was desirable in the late 1800s but exposed as disadvantageous (because it was associated with less healthy babies) in the twentieth century.

But, the actual empirical evidence about the connection between maternal prenatal weight gain and fetal size has been all over the map, with some researchers attesting to their close (probably causal) correlation while others contend that the association is a deception. In the decades around 1900, the correlation was widely accepted. Then researchers challenged it. In 1935 one writer asserted that “there is not the least bit of scientific evidence to show that you can have a smaller baby by restricting your diet.”[51]In a 1945 scholarly article, two authors agreed that there was absolutely no correlation between maternal weight gain and a baby’s birthweight.[52] Then researchers reconsidered, disagreed with one another, and forwarded more nuanced opinions. In the 1960s, for example, one article suggested that there was a small correlation: “only about 2.5% of the maternal weight gained beyond 10 lb. can be demonstrated as additional fetal weight,” the authors proclaimed in Obstetrics and Gynecology.[53]The next year, in the same journal, a separate research team concluded that there was a “strong association between weight gain during pregnancy, prepregnancy weight of the mother, and the birth weight of the baby.”[54] Put simply, studies have investigated the relationship between maternal weight gain during pregnancy and birthweight multiple times over in every decade since the late 1800s, and they have all reached different conclusions.

Recent evidence does indicate that weight gain during pregnancy is at least related to gestational weight, and babies that are either too big or too small for their gestational age can both be problematic. In a 2009 publication reevaluating guidelines on weight gain during pregnancy, a group of expert authors explained that “many epidemiologic studies are consistent in showing a linear, direct relationship between GWG [gestational weight gain] and birth weight for gestational age.” Although, as Emily Oster comments, the effects are small on an individual basis.[55]

2. Complications – for mother and babyA second major point of continuity in this literature is the question of whether maternal weight gain during pregnancy has any bearing on maternal or fetal complications, ranging from toxemia/preeclampsia to delivery problems. Evidence substantiates, for example, that “excessive” gestational weight gain raises a woman’s chances of having a C-section. (Toxemia is the former nomenclature for preeclampsia, a late-pregnancy condition whose symptoms include hypertension, excessive swelling, severe headaches, and vision problems. It can be serious; for more on the condition, check out this patient information pamphlet from the U.K.)[56]

3. Postpartum Weight Retention and ObesityThere is a long record of concerns about how prenatal weight gain could lead to overall weight gain beyond childbearing, but around the mid-1900s that escalated to encompass broad social anxieties about obesity. The rhetoric from the mid-twentieth century indicates that contemporaries took obesity seriously. It was a grave concern. Again, though, it’s unclear whether prenatal weight gain is necessarily a determining factor in women’s weight beyond their childbearing years. In one early study (from 1969), just as an example, the authors determined permanent weight gain after pregnancy based on women’s six-week postpartum checkups.[57]I can’t speak for everyone, but it took me months to drop the 30 pounds I put on while I was pregnant; measuring longitudinal weight gain just six weeks after delivery could obviously lead to unsound conclusions. In the twenty-first century, investigators are using more appropriate postpartum measuring points, ranging from 30ish to 50ish weeks after delivery, but the extent to which gestational weight gain influences a woman’s weight overall is still uncertain.[58]

Recently, this issue has broadened more, as physicians and researchers are using epigenetics to link “excessive” prenatal weight gain not just to obesity in women, but also to their children and the societal obesity epidemic. Some studies indicate that obese women are nearly two times more likely to have a stillbirth than women of normal weight, and that their babies are almost three times more likely to die in the first month of life.[59] But these links are still tenuous. The evidence is much more clear that women who gain more weight while they are pregnant bear children who are more likely to be overweight and have higher blood pressure in childhood, as well as more likely to develop diabetes, heart disease and cancer as adults.[60]

Recommendations Vs. RealityUnderlying all this changing advice and shifting ideologies is the basic question of what constitutes “normal” weight gain during pregnancy. What is “ideal”? What is “excessive”?

In 1990, Roy Pitkin, an obstetrician at UCLA, reflected that the more recent, “loose” guidelines of the late-twentieth century “in a sense . . . bring health recommendations in line with what is actually happening.”[61] Looking at available historical evidence, he was exactly right.​It is fascinating that throughout this record, there has always been some level ofdisconnect between what medicine and society were promoting as the “ideal” weight gain and what pregnant women typically gained. Even when doctors were adamant that women keep their weight gain in the range of 10-15 pounds, they were cognizant of a different reality - medical articles regularly acknowledged a much higher typical weight gain range than the recommended limits. To illustrate this difference, I put together a timeline with some available evidence indicating how much weight women were actually gaining (as documented in studies or witnessed by practicing obstetricians), rather than what they ought to be gaining. To a certain extent, these figures – which document “real” weight gain during pregnancy – were more consistent across time than were prescriptions advising women how much to gain (. . . until the 2000s, that is). Still, you can see that there is a general trend towards higher gain, and numbers shifted notably upwards after the 1970s guidelines were released. Take a look:

1920, textbook: “The mother’s gradual but consistent gain in weight amounts finally to about 30 pounds; exceptionally, it is as little as 10 to 15 pounds, and at the other extreme as much as 40 to 50 pounds.”[62]

1935, advice book: Women’s “average gain is around twenty pounds.” (The author notes that the maximum should be 25 pounds for a woman of normal weight, and that “further gain . . . is not desirable.”)[63]

1944, medical article: a frequently-cited review of almost 12,000 patients across 19 studies, determined that the average weight gain for normal pregnancies was 24 pounds.[64]

1945, medical article: determined that average maternal weight gain was 21 pounds but that the range was much wider, from -3 pounds to +48 pounds.[65]

1963, clinical article: “It is generally agreed that a weight gain of 20 to 24 pounds during pregnancy can be regarded as normal . . . About 20 per cent of obstetric patients will exceed these limits . . . .”[67]

1968, medical article: a study of more than 12,000 women revealed an average weight gain of 22 pounds.[68]

1969, medical study: Women’s average weight gain was 24 pounds, although the authors made note of wide variation. (They recommended an “ideal” gain of 17 pounds and regarded gain higher than 30 pounds as in the “danger level.”)[69]

1970, medical article: most women’s average weight gain was 20 to 24 pounds.[70]

After this, women have been gaining more weight on average during their pregnancies. One study published in 2000 put together a nice chart illustrating this – check it out here. “Crude data clearly show,” the authors stated, “that after weight-gain recommendations were liberalized, there was an increase in the means [averages] of both pregnancy weight gain and infant birth weight.”[71]From 1990 to 2005, a clear majority of pregnant women in the U.S. gained between 16 – 40 pounds; the mere fact that the window has expanded to incorporate 40-pound gains – which would have been far outside the standard range of deviation for most of the 1900s – is telling.

Medicine has always acknowledged that diet is crucially important to a healthy pregnancy, but it has never been sure how to advise pregnant women about their weight.

Doctors see all kinds of different patients and outcomes, and clearly, research has failed to provide them with comprehensive answers. Take this suggestion from a physician in 1949: he encouraged his colleagues to remember “the basic principle that we are treating individuals rather than conditions in our maternity practice,” and reminded them that “wide fluctuations from so-called normal patterns can often be observed with complacency.”[72] In 1975, one piece observed that “the wide range of weight gain in pregnancy compatible with a normal outcome is astonishing – from a loss of more than 5 pounds to a gain of more than 50 pounds . . . .”[73]

Indeed, physicians have been trying – for decades – to contend with the fact that they don’t know what “normal” is. In 1962, physician P. Rhodes wrote in The Lancet that “weight gain in pregnancy is still a source of much confusion.”[74] Reflecting on their evidence from a study in the 1960s, authors wrote that “uncomplicated patients may gain a wide variety of weight with impunity.” Thus, they said, “a clinically useful concept of ‘normal weight gain’ could not be determined.” (They did, however, “venture to conclude that the ideal weight gain during pregnancy is somewhere between 16 and 20 lb., most likely about 18 lb.”[75]) A separate group of researchers observed, in 1970, that “weight gain in pregnancy has been studied for over 100 years but there is still no agreement as to the amount that can be regarded as normal.”[76] Five years later, another team explained how doctors’ knowledge regarding nutrition generally is “deficient because formal instruction in nutritional principles in most medical schools is absent or cursory.”[77]

If this science has always had a murky quality to it, why consider it? As usual, the past cannot supply us with answers, but it can give us some things to think about. Sweeping through the unresolved history of “eating for two,” three useful threads of continuity stood out to me:

1. Pregnant women should focus on eating healthfully.Eating well while pregnant is beneficial for women and babies. Since the data and numbers about exactly how much weight to gain have been so irregular, maybe it’s best not to get too bogged down in them and expend your energy focusing on eating well. That’s going to mean different things for different people. (Michael Pollan, anyone? Here’s a list of his food rules.) Furthermore, medicine has expressed increasing appreciation for the importance of achieving a healthy pre-pregnancy weight. Quite simply, more and more studies have come out indicating that having a normal weight before pregnancy matters a great deal, for a great many reasons.[78] Indeed, the return towards a more restricted, conservative perspective on weight gain during pregnancy – one characterized by minimalism rather than laxity – stems in large part from concerns about society’s weight gain in general, not necessarily with weight gain during pregnancy, per se.

2. Moderation has never been controversial.It sounds obvious, but it is clear and consistent in the historical record that the most contentious lines of debate about weight gain during pregnancy have fallen on the edges of the bell curve, where severe dietary restriction and excessive weight gain lie. It’s a subjective determination, and it feels hollow, but it stands the test of time. (Note that weight gain and malnutrition are not the same – weight gain, be it high or low, is not necessarily indicative of nutrition.)

3. There is no indication to “eat for two” while pregnant.This has, as I suggested earlier, been one of the only unanimous points of agreement about weight gain in pregnancy over time. Pregnant women do not need to eat much more. (“Eating for two?” health economist Emily Oster asks – “you wish.”)[79]Science has been “trending” towards the “less is more approach” for 150 years (at least).

The concept of “eating for two” has misled and confused pregnant women for centuries. Some authors are working to reclaim the old saying as an impetus for dietary improvements instead of dietary exemptions (quality over quantity), but the very fact that such a mistaken phrase has survived for so long does not bode well for its future. In the end, I couldn’t pin down the origins of the idea to “eat for two,” but I did learn that at no point in time has anyone knowledgeable ever thought it was a good idea.